The Left has traditionally assumed that human nature is so malleable, so perfectible, that it can be shaped in almost any direction. By contrast, a Darwinian science of human nature supports traditionalist conservatives and classical liberals in their realist view of human imperfectibility, and in their commitment to ordered liberty as rooted in natural desires, cultural traditions, and prudential judgments.

Sunday, April 26, 2009

The Idea of Nature, Part 1

The English word nature is derived from the Latin word natura, which is related to the verb nasci (to be born) and the noun natus (birth). The Latin natura corresponds to the Greek phusis, of which the root is phuo (growing, becoming, being). This etymology suggests that nature is the original birth or coming into being of something. More generally, nature is concerned with "first things," the origins of things.

The idea of nature was first formulated by ancient Greek philosophers and scientists. Aristotle identified the "first philosophers" as "humans who spoke about nature" in looking for the "principles" or "beginnings" of all things.

These Greek philosophers thought of phusis as the beginning or coming to be of something. But more often phusis meant the sort or kind or description of something--the distinctive character of a thing or class of things. The nature of something could be what it is at birth, or it could be what it grows into at maturity, what it is at its beginning or at its end. "Nature is an end," Aristotle claimed, "because whatever anything is like when its growth is completed, that we call the nature of each thing." These Greek philosophers began by asking about the nature of each thing, what each thing is like. Thus, the Greek philosopher Parmenides could write a book with the title On Nature, which considered the "nature" of everything.

When nature becomes everything, it is impossible to define. But generally nature is a term of distinction, and so its meaning can be clarified by asking what is its opposite. In ancient Greece, "nature" (phusis) was most commonly set in opposition to "custom" (nomos) or "art" (techne). Custom and art are human products. By contrast, nature is what arises on its own without human interference. Nature is what is not customary or artificial. (The simple dichotomy becomes dubious, however, as I will suggest later, when we consider how natural potentialities or inclinations depend on habit, culture, or art for their completion.)

Philosophy or science arose in ancient Greece when a few thinkers noticed that customary practices and beliefs varied across human societies. This led them to doubt the authority of human customs and to look for what was universally true by nature as opposed to what was believed to be true by human custom. Whatever arises by human custom or artfulness is changeable, but what arises by nature, it was argued, is unchangeable and thus more real than the perishable products of human activity. And yet, biologists such as Aristotle could see that living beings show a natural contingency or historicity in their coming into being, growing to maturity, and passing away.

The ultimate justification for customary practices and beliefs can be the claim that they are divine, that they originated from the commands of gods or god-like ancestors. But when Greek philosophers and scientists explained the "first things" as natural rather than customary or artificial, this suggested that even the gods might be artificial or human-made, as being products of storytelling. The natural was opposed to the divine or the supernatural. Consequently, as indicated by the Athenian trial and execution of Socrates, who was charged with impiety, the philosophic discovery of nature implied a questioning of the gods.

The religious believer could respond by denying the idea of nature as the autonomous order of the world and affirming that whatever exists is what it is only through the creative activity of the gods or God. The Hebrew scriptures contain no word that corresponds to nature. In the Greek New Testament, the word phusis does not occur except in the letters of Paul, who was influenced by Greek philosophy. Nevertheless, some interpreters of the Bible have argued that it assumes the existence of a natural order of things, even if that natural order depends ultimately on God's creative will.

Among many early and medieval Christian theologians, the Greek idea of nature was adopted, but with the understanding that this nature was created by God. This allowed Thomas Aquinas, for instance, to interpret the order found in the cosmos as "eternal law" and in human nature as "natural law." The natural law of what it is to be human was manifest in three levels of natural inclination or desire: for physical life, for family and children, and for political and rational experience.

In the late medieval period, as creation itself increasingly came to be conceived in technological terms, this led to nature being thought of as God's artifice. As a divine construction, nature could stand on its own and was governed by its own "secondary laws." Although God ultimately remained the transcendent "first cause" of all things, the divine began to be pushed to the margins of scientific inquiry.

The founders of modern science such as Galileo Galilei, Francis Bacon, Robert Boyle, and Isaac Newton adopted this medieval teaching in defending the science of nature as the study of "secondary causes," as distinguished from Biblical theology as the study of God as "first cause." Nature was the book of God's works, and the Bible was the book of God's words. To understand nature, scientists must strive to understand the principles of nature that constituted the laws of nature. Charles Darwin appealed to this "two books" idea to justify his scientific study of living nature.

Some people have seen a contrast between the fundamentally theoretical understanding of nature in premodern science and the fundamentally technological understanding of nature in modern science. Premodern scientists seem more concerned with the intelligibility of nature, while modern scientists seem more concerned with the mastery of nature. Modern scientists under the banner of Bacon and Descartes seem to strive for power over nature, so that the point is not just to understand nature but to change it, and thus modern science seems to manifest an inherently technological orientation. As I will suggest, however, in some subsequent posts, I think this sharp contrast between premodern and modern science is overstated: even if modern science tends to stress the technological conquest of nature, modern science is still motivated by the same natural desire for understanding that drove premodern science.